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Media type:
E-Article
Title:
New gravity-derived bathymetry for the Thwaites, Crosson, and Dotson ice shelves revealing two ice shelf populations
Contributor:
Jordan, Tom A.;
Porter, David;
Tinto, Kirsty;
Millan, Romain;
Muto, Atsuhiro;
Hogan, Kelly;
Larter, Robert D.;
Graham, Alastair G. C.;
Paden, John D.
Published:
Copernicus GmbH, 2020
Published in:
The Cryosphere, 14 (2020) 9, Seite 2869-2882
Language:
English
DOI:
10.5194/tc-14-2869-2020
ISSN:
1994-0424
Origination:
Footnote:
Description:
Abstract. Ice shelves play a critical role in the long-termstability of ice sheets through their buttressing effect. The underlyingbathymetry and cavity thickness are key inputs for modelling future icesheet evolution. However, direct observation of sub-ice-shelf bathymetry istime-consuming, logistically risky, and in some areas simply not possible.Here we use new compilations of airborne and marine gravity, radar depthsounding, and swath bathymetry to provide new estimates of sub-ice-shelfbathymetry outboard of the rapidly changing West Antarctic Thwaites Glacierand beneath the adjacent Dotson and Crosson ice shelves. This region is ofspecial interest, as the low-lying inland reverse slope of the ThwaitesGlacier system makes it vulnerable to marine ice sheet instability, withrapid grounding line retreat observed since 1993 suggesting this process maybe underway. Our results confirm a major marine channel >800 mdeep extends tens of kilometres to the front of Thwaites Glacier, while theadjacent ice shelves are underlain by more complex bathymetry. Comparison ofour new bathymetry with ice shelf draft reveals that ice shelves formedsince 1993 comprise a distinct population where the draft conforms closelyto the underlying bathymetry, unlike the older ice shelves, which show a moreuniform depth of the ice base. This indicates that despite rapid basalmelting in some areas, these recently floated parts of the ice shelf are notyet in dynamic equilibrium with their retreated grounding line positions andthe underlying ocean system, a factor which must be included in futuremodels of this region's evolution.